Removable plastisol liners for crowns



Feb. 8, 1966 J. J. WATERS 3,233,770

REMOVABLE PLASTISOL LINERS FOR CROWNS Filed March 5, 1963 INVENTORATTORNEYS United States Patent 3,233,770 REMOVABLE PLASTISOL LINERS FORCROWNS Joseph J. Waters, Abington, Pa., assignor to Crown Cork & SealCompany, Inc., Philadelphia, Pa., a corporation of New York Filed Mar.5, 1963, Ser. No. 262,961 13 Claims. (Cl. 2154-0) This invention relatesto closures containing clear plastic liners.

In the promotion of various soft drinks, it has been proposed to mailthe crown closure from the bottle back to the manufacturer. The PostOflice Department has objected to the sending of crowns through the mailsince the automatic cancelling machines are frequently damaged thereby.

It has not been possible in the past to prepare an over-all crownclosure liner of the plastisol type which would efiectively seal abottle but still be readily removable, eg, to be suitable for mailing.

It is an object of the present invention to make a closure having aplastic liner which is readily removable.

Another object is to prepare a closure having a liner which is readilyremovable but which prior to removal acts as an effective sealant toprevent leaks in bottles closed by said closure.

Another object is to devise a simple way of removing a clear plasticliner having printing on the under portion thereof from a crown closure.

Still further objects and the entire scope of applicability of thepresent invention will become apparent from he detailed descriptiongiven hereinafter; it should be understood, however, that the detaileddescription and specific examples, while indicating preferredembodiments of the invention, are given by way of illustration only,since various changes and modifications Within the spirit and scope ofthe invention will become apparent to those skilled-in the art from thisdetailed description. It has now been found that these objects can beattained by adhering a plastic liner to a closure shell in such afashion that the liner adheres to the closure shell only in certainareas and does not adhere in other areas. While the invention is ofprimary utility with liners for crown closures, it is also useful inconnection with liners for other types of closures such as a lug, screwon and press on caps.

The present invention will be best understood in connection with theattached drawings wherein:

FIGURE 1 is a sectional view of a crown closure cap with a formedplastisol liner;

FIGURE 2 is a bottom view of the cap prior to formation of the plastisolliner therein;

FIGURE 3 is a bottom view of the cap after the formation of theplastisol liner;

FIGURE 4 is a view of the cap showing the liner partially removed; 5

FIGURE 5 is a view of the liner after removal of the liner; and

FIGURE 6 is a bottom ,view of a crown closure illustrating analternative form of the invention.

Referring more specifically to the drawing the numeral 2 indicates ametal, e.g. tin-plated steel, crown shell having a fluted skirt 4 and anoverall vinyl resin lacquer protective coating 6. The lacquer is ofconventional character and in the specific example was a mixture of 80%of a vinyl chloride-vinyl acetate copolymer (87% vinyl chloride) together with 20% of an elecresinous modifier, specifically tung oilmodified phenylphenolformaldehyde resin dissolved'in an organic solvent,specifically 70% xylene and 30% isophorone. The solvents were removed byvolatilization after the lacquer was applied to the cap and prior toapplication of any 3,233,770 Patented Feb. 8, 1966 ice superimposedlayer. Other suitable vinyl resin lacquers are those disclosed in PatentNo. 2,380,456.

In the central portion of the cap on top of the lacquer 6 there isprinted indicia 8 made of a lithographic printing ink. In the specificexample there was used General Printing Ink No. 3504 red. Thelithographic ink can be of any other color, e.g. black, blue, brown,green or white. The lithographic printing ink can also be transparentand this is frequently desired. A suitable transparent lithographicprinting ink is General Printing Ink No. 95836. Superimposed on thelacquer coating and the printed indicia is a vinyl chloride plastisol,liner 10 formed so as to include a sealing ring 12. In the specificexample, the plastisol was unfoamed clear and colorless (water white) sothat the indicia could be seen therethrough. However, if it is desired,the plastisol can be colored with an appropriate dye to make a clearcolored liner or a pigment, e.g. carbon black, calcium carbonate,titanium dioxide, ochre, iron oxide or the like, can be added to renderthe plastisol opaque so that the indicia cannot be seen until removal ofthe liner. This 'is frequently desirable in promotion of the productpackaged.

As stated, however, in the specific example, the plastisol was clear andcolorless. It was made up of the following formulation with the partsbeing by weight:

Parts Exon 654 (70 poise) 46.3 Geon 202 18.0 Dioctyl phthalate 35.5Dibutyl p-cresol (antioxidant) 0.2

Geon 202 is a copolymer of 94% vinyl chloride and 6% vinylidene chlorideand Exon 654 is a copolymer of vinyl chloride with a small amount andnot over 5% of trichloroethylene.

The plastisol is applied to the center of the crown cap 2 as a blob. Itcan then be spread to form the liner in any conventional fashion, e.g.by spinning as in Foye patent, No. 2,489,407 or by use of a plunger asin Gora patent, No. 2,548,306 or Normandy patent, No. 3,002,- 641. Forconvenience a heated stepped plunger was used as set forth in theNormandy patent in making the closure liners shown in the drawings.

The plastisol adhered to the vinyl resin lacquer coating 6 but did notadhere to the printed indicia 8. In order to have adequate sealing, itis critical that there be good adhesion to the cap in the area of thesealing ring and in the immediately adjacent inner area. If this area isleft unprinted, the plastisol will adhere to it tenaciously and preventundesired removal of the liner under the capping pressure. Generally ina crown cap having an inner diameter of about 1 inch, the center /2 inchof the liner need not be adhered tenaciously to the cap and also thearea of the liner outside the sealing ring 12 need not adhere to thecap. 7 Consequently, these areas can be printed to prevent adhesion andthen subsequently after the crown is removed from the bottle, can orother container, the liner is pulled out.

FIGURE 2 shows the crown 2 bottom surface having printed indicia 8thereon prior to application of the plastisol. FIGURE 3 is a viewsimilar to FIGURE 2 after the plastisol has been applied and spread toform a liner 10 having a sealing ring 12. Since the liner is made ofclear, water white plastic, the indicia are visible therethrough. FIGURE4 is a view showing the manner of removing the liner 10 from the cap.The portion of the liner indicated at 14 has been separated from thecap. FIGURE 5 shows the liner 10 completely remove-d from the cap.

If the printing is underbaked prior to aplication of the plastisol, itwill offset on the liner. Offset letters 16 are 3 shown on the liner inFIGURE 5. The liner that has been removed and which contains the offsetprinting can be sent through the mails, e.g., in a contest, without damaging automatic cancelling machines.

FIGURE 6 shows an alternative form of the invention wherein there isprovided a metal crown closure 2. The closure has a coating of a vinylresin lacquer of the type set forth above. A doughnut shapedlithographic printing ink, overprint 18, is then applied. The ink can beG.P.I. No. 3504 red or can be of other color or can be a transparentink. There is then applied to the center of the cap a vinyl chloridepolymer plastisol of the type previously set forth, and it is formedinto an over-all liner having a sealing ring 12 in the manner previouslyset forth. The doughnut shaped overprint 18 is between the skirt 20 andthe sealing ring 12. The liner can be readily removed from the cap sincethere is no adhesion between the doughnut 18 and the overlying portionof the liner. Sealing of the bottle or other container to which theclosure is applied is insured since the outer portion of the liner issecurely locked between the cap skirt and the glass surface of thebottle. However, after removal of the cap from the bottle, it is an easymatter to remove the liner by starting the removal at the doughnut whichdoes not adhere to the vinyl resin lacquer. In this species of theinvention, there can also be indicia printed over the lacquer in thecentral portion of the cap but outside of the critical sealing area.Alternatively, the indicia can be applied to the bottom of the capbefore applying the vinyl lacquer. In this latter case, since theindicia will not be between the lacquer and the plastisol liner, theindicia will not be removed upon removal of the liner (starting with thedoughnut) from the cap.

Unless otherwise indicated, all parts are by weight.

In addition to the above-mentioned plastisol formulation, there can beused numerous other plastisols. Typical preferred examples are given inTable 1.

Formulation A can be rendered opaque to give an opaque liner byincluding 0.25 part titanium dioxide and 0.25 part carbon black.

While preferably the plastisol liner is clear and unfoamed, there canalso be used foamed plastisol liners made, for example, as disclosed inthe aforementioned Normandy patent.

A vinyl chloride plastisol may be described as a mixture of a vinylchloride resin with a plasticizer in which the resin is essentiallyinsoluble at room temperature, or very slowly soluble at roomtemperature, but in which it is essentially completely and rapidlysoluble at some elevated temperature, or slowly soluble on standing atroom temperature. When such a mixture is heated, the resin dissolves inthe hot plasticizer and, when the solution cools, a permanent gel isformed. A plastisol has also been defined as a semi-liquid pastecomposition containing a normally liquid plasticizer and a vinylchloride resin which is paste forming with the plasticizer at atemperature below the fluxing temperature of the resinplasticizercomponents and capable, upon being heated to the fluxing temperature ofthe resin-plasticizer components, of forming a permanent rubbery gel.

As the vinyl chloride resin, there can be used homopolymers, such asGeon 101 (mol. wt. about 82,000); Vinylite QYNV and Geon 121 (mol. wt.about 89,000).

There can also be used copolymers of vinyl chloride with a minor amountof copolymerizable ethylenically unsaturated material. Generally, thecopolymerizable material is used in an amount of 20% or less, andpreferably 10% or less, e.g., 5%. As illustrative copolymerizablematerials, there can be used vinyl acetate, vinylidene chloride,aicrylonitrile, trichloroethylene, maleic anhydride, diethyl maleate,and other alkyl maleates, etc. Specific examples of copolymers areVinylite VNYV (copolymer of vinyl chloride-5% vinyl acetate); Exon 654(vinyl chloride copolymerized with not over 5% trichloroethylene);Pliovic AO (vinyl chloride copolymerized with not over 5% of a dialkylmaleate); Vinylite VYHH (copolymer of 87% vinyl chloride with 13% vinylacetate); Vinylite VMCH (a copolymer containing 86% vinyl chloride, 13%vinyl acetate and 1% malcic anhydride); Geon 202 (copolymer of 94% vinylchloride and 6% vinylidene chloride).

The preferred plasticizer is dioctyl phthalate (di-2- ethylhexylphthalate), although other conventional vinyl chloride plastisolplasticizers can be used, such as other alkyl phthalates, e.g., butyldecyl phthalate, octyl decyl phthalate, diisodecyl phthalate,di-isooctyl phthalate, didecyl phthalate, di-dodecyl phthalate, butylphthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methylphthalyl ethyl glycolate, and other alkyl phthalyl alkyl glycolates,acetyl tributyl citrate, diisobutyl adipate, butyl benzyl phthalate,didecyl azelate, dioctyl .azelate, dioctyl adipate, dioctyl sebacate,dibutyl sebacate, and other dialkyl esters of alkane dicarboxylic acids,trioctyl phosphate, tricresyl phosphate and other triaryl phosphates,tetrahydrofurfuryl alcohol esters, e.g.,' tetrahydrofurfuryl adipate,low viscosity polyesters, e.g., polyethylene glycol adipate,polyethylene glycol adipate-maleate, alkyl esters of higher fatty acids,e.g., pelargonic acid and mixtures of two or more of these plasticizersor one or more primary plasticizers with one or more secondaryplasticizers can be used.

Preferably, there is present a stabilizer for the vinyl chloride. Foreach parts of vinyl chloride resin there are used 1 to 10 parts ofstabilizer. Good stabilizers are Thermolite 31 (a thio organic tincompound), Stayrite No. 90 (a mixture of metallic soaps, predominantlycalcium, aluminum and zinc stearates, with a minor amount of other fattyacid salts), cadmium laurate, barium laurate, calcium stearate,magnesium stearate, aluminum stearate, zinc stearate, and other fattyacid soaps of these metals, alkyl and aryl tin compounds, dibutyl tinoxide, trioctyl, phosphite, cadmium and barium epoxy compounds, diphenylurea, polyethylene glycol adipate and adipate-maleate, etc.

While it is preferred to use lithographic printing inks to serve as thenon-adhesive portion between the lacquer 6 and the plastisol, there canbe used any other non-adhesive. Thus, there can be used silicone fluidsand greases such as polydimethyl-siloxane.

While plastisols are the preferred plastic liners, there can also beused plastic liners from polyethylene, polypropylene, irradiatedpolyethylene, polystyrene, polyurethane, e.g., toluenediisocyanate-polypropylene glycol 2025 condensation product;polyethylene terephthalate and other polyesters, polycarbonates, e.g.,the condensation product of bisphenol A and diphenyl carbonate.

What is claimed is:

1. A closure shell having an overall plastic liner adhered directlythereto with predetermined portions of the closure shell having acoating which is nonadherent to the liner whereby the liner can bereadily removed from the. shell.

2. A closure shell according to claim 1 wherein in said predeterminedportions there are printing indicia as said nonadherent coating betweensaid shell and said liner.

3. A closure shell according to claim 1 wherein in said predeterminedportions there is a polysilixane as said nonadherent coating betweensaid shell and said liner.

4. A closure shell having an inner vinyl resin lacquer coating and anoverall vinyl chloride plastisol liner adhered directly to said lacquercoating with predetermined portions of the lacquer having a coatingwhich is nonadherent to the liner whereby the liner can be readilyremoved from the shell.

5. A closure shell according to claim 4 wherein in said predeterminedportions there is lithographic printing ink as said nonadherent coatingbetween said shell and said liner.

6. A closure shell according to claim 5 wherein the printing ink is atransparent printing ink.

7. A crown closure shell having an inner vinyl resin lacquer coating andan overall vinyl chloride plastisol liner, said liner comprising asealing ring, said liner being strongly and directly adhered to saidlacquer in the area of the sealing ring and in the area immediatelyinside said sealing ring, said lacquer having a coating which isnonadherent to said liner in other portions of the lacquer whereby saidliner can be readily removed from said shell.

8. A closure shell according to claim 7 wherein in said other portionsthere is a lithographic printing ink as said nonadherent coating betweensaid lacquer and said liner.

9. A closure shell according to claim 8 wherein said shell includes askirt and said other portions of the liner are between said skirt andsaid sealing ring.

10. A closure shell according to claim 9 wherein said plastisol liner isa clear plastisol.

11. A closure shell according to claim 7 wherein said plastisol liner isa clear plastisol.

12. A closure shell according to claim 11 wherein in said other portionsthere is a lithographic printing ink as said nonadherent coating betweensaid lacquer and said liner.

13. A process comprising removing a vinyl chloride resin plastisol linerhaving ofiset printing thereon from a closure shell having an innervinyl resin lacquer coating, predetermined areas between said lacquercoating and said liner having a lithographic printing ink thereinwhereby said areas are less adherent than the remaining po'rtions ofsaid lacquer and said liner, said liner having been formed over said inkbefore said ink has fully set whereby said olfset printing is retainedby said liner when it is removed from the shell, said removal commencingat said less adherent portions.

References Cited by the Examiner UNITED STATES PATENTS 1,711,469 4/1929Stratford 2l5-1 2,055,625 9/1936 Heckel et al. 215-39 2,718,323 9/1955Kennedy 2l540 2,946,471 7/1960 Randiett 2l5405 3,005,433 10/1961 Risch.

3,018,911 1/1962 Grumbles et a1. 21540 3,021,250 2/1962 La Voie 156247 X3,032,433 5/1962 Lewis et a1. 156247 FOREIGN PATENTS 843,783 8/1960Great Britain.

LOUIS G. MANCENE, Acting Primary Examiner.

THERON E. CONDON, Examiner.

1. A CLOSURE SHELL HAVING AN OVERALL PLASTIC LINER ADHERED DIRECTLYTHERETO WITH PREDETERMINED PORTIONS OF THE CLOSURE SHELL HAVING ACOATING WHICH IS NONADHERENT TO THE LINER WHEREBY THE LINER CAN BEREADILY REMOVED FROM THE SHEEL.